Secret: #readonly, #readwrite, #noaccess add abstract & type restrictions

src/crypto-secret/secret.cr

@@ -33,7 +33,7 @@ module Crypto::Secret
 
   extend ClassMethods
 
-  # For debugging.
+  # For debugging.  Leaks the secret
   #
   # Returned String **not** tracked or wiped
   def hexstring : String
@@ -92,6 +92,7 @@ module Crypto::Secret
     wipe
   end
 
+  # Wipes data & makes this object available for reuse
   def reset
     wipe
   end
@@ -132,13 +133,20 @@ module Crypto::Secret
     end
   end
 
-  # Marks a region allocated using as read & write depending on implementation.
+  # Marks a region as read & write depending on implementation.
   abstract def readwrite : self
-  # Marks a region allocated using as read-only depending on implementation.
+  # Marks a region as read-only depending on implementation.
   abstract def readonly : self
-  # Makes a region allocated inaccessible depending on implementation. It cannot be read or written, but the data are preserved.
+  # Makes a region inaccessible depending on implementation. It cannot be read or written, but the data are preserved.
   abstract def noaccess : self
 
+  # Temporarily marks a region as read & write depending on implementation and yields `Bytes`
+  abstract def readwrite(& : Bytes -> U) forall U
+  # Temporarily marks a region as readonly depending on implementation and yields `Bytes`
+  abstract def readonly(& : Bytes -> U) forall U
+  # Temporarily Makes a region inaccessible depending on implementation. It cannot be read or written, but the data are preserved.
+  abstract def noaccess(& : Bytes -> U) forall U
+
   protected abstract def to_slice(& : Bytes -> U) forall U
   abstract def bytesize : Int32
 

src/crypto-secret/stateful.cr

@@ -40,7 +40,7 @@ module Crypto::Secret
 
     # Temporarily make buffer readonly within the block returning to the prior state on exit.
     # WARNING: Not thread safe unless this object is readonly or readwrite
-    def readonly
+    def readonly(& : Bytes -> U) forall U
       with_state State::Readonly do
         to_slice do |slice|
           yield slice

src/crypto-secret/stateless.cr

@@ -20,7 +20,7 @@ module Crypto::Secret::Stateless
   # `slice` is only available within the block
   #
   # Not thread safe
-  def readwrite
+  def readwrite(& : Bytes -> U) forall U
     to_slice do |slice|
       yield slice
     end
@@ -35,7 +35,7 @@ module Crypto::Secret::Stateless
   # Don't write to it
   #
   # Not thread safe
-  def readonly
+  def readonly(& : Bytes -> U) forall U
     to_slice do |slice|
       yield slice
     end
@@ -47,7 +47,7 @@ module Crypto::Secret::Stateless
   end
 
   # Not thread safe
-  def noaccess
+  def noaccess(& : Bytes -> U) forall U
     yield
   end